The Imaging Core has two components that provide major support to the center investigators. The Confocal/Multiphoton Component provides the following: 1) high resolution 3-dimensional imaging of parameter-sensitive fluorophores in living cells and tissues by laser scanning confocal and multiphoton microscopy to monitor ions, electrical potentials, oxygen and nitrogen radical generation, pyridine nucleotide reduction, mitochondfial and plasmalemmal membrane permeability, and cell viability (apoptosis and necrosis); 2) intravital microscopy using "real time" confocal microscope and multiphoton microscopy to monitor microcirculation, leukocyte margination and gene expression in living animals; 3) high resolution confocal and multiphoton imaging of tissue sections for immunocytochemistry and green fluorescent protein; 4) a digital darkroom facility for digitizing images, analyzing and labeling these images, and printing the processed images as photographic quality prints and slides for use in publications, reports and oral presentations; and 5) a fluorescence plate reader for measuring cell viability and intracellular ions in cultured cells grown on multi-well plates. The Pathology Component provides consultation, training and services in basic histopathology for preparation of frozen and paraffin sections for histology and immunocytochemistry. The Pathology Component routinely handles H&E, PAS, eosin, and trichrome staining of brain, liver and other tissues and provides immunocytochemical staining for various cellular components of interest.